High-speed photography (up to 500 pictures/sec) will be used to determine the wetting and spreading characteristics of tear fluid over the anterior surface of the eye, both in normal and dry-eyed individuals, and with and without contact lenses present. Particulate matter, such as carbon lampblack, can aid in visualization of the movements of the tear fluid. With the aid of an image intensifier devise on the high-speed camera, fluorescein dye can also be used to observe possible flow patterns and fluid exchange around and beneath hard and soft contact lenses. The actions of the blinking lids in facilitating tear mixing and drainage has been under investigation in this study, and will continue into the next project period. Particular emphasis will be made concerning ocular surfacing abnormalities associated with various classes of dry eye symptoms. The effectiveness of artificial tear preparations is also being examined.